When a young woman named Ashley is found drowned in a ball gown in the pond outside Belvedere Castle, Mac (Gary Sinise) and his team drain the pond to search for clues. York will play Krista, the classy, wealthy mother of Ashley's boyfriend, Matthew (Alex Ashbaugh). When he becomes a suspect, Krista accuses Ashley's ex-boyfriend Matthew, who will be played by Nicotera.

The episode, which is slated to air in early November, will be filmed on location in New York.

Besides playing the congresswoman ex-wife of Richard Schiff's Toby Ziegler on The West Wing, York has also appeared on such shows as NCISand Body of Proof. She most recently recurred on The Client Listas Jolene, the masseuse who didn't offer any "extras" to her clients. Nicotera is best known for his role as Ratboy, a prospect for the motorcycle club at the center of FX's Sons of Anarchy.CSI: NY premieres Friday, Sept. 28 at 8/7c on CBS.